Buggy code:
public class DefsTest extends CleanupHelper { @ Test public void ensureStaticCFMIdsAreLessThan1000 ( ) { } @ Test public void testInvalidNames ( ) throws IOException { } @ Test public void saveAndRestore ( ) throws IOException { } @ Test public void addNewCfToBogusTable ( ) throws InterruptedException { } @ Test public void testMigrations ( ) throws IOException , ConfigurationException { } @ Test public void addNewCF ( ) throws IOException , InterruptedException , ExecutionException , ConfigurationException { } @ Test public void dropCf ( ) throws IOException , InterruptedException , ExecutionException , ConfigurationException { } @ Test public void renameCf ( ) throws IOException , InterruptedException , ExecutionException , ConfigurationException { DecoratedKey dk = Util . dk ( "key0" ) ; final KSMetaData ks = DatabaseDescriptor . getTableDefinition ( "Keyspace2" ) ; assert ks != null ; final CFMetaData oldCfm = ks . cfMetaData ( ) . get ( "Standard1" ) ; assert oldCfm != null ; RowMutation rm = new RowMutation ( ks . name , dk . key ) ; for ( int i = 0 ; i < 100 ; i ++ ) rm . add ( new QueryPath ( oldCfm . cfName , null , ( "col" + i ) . getBytes ( ) ) , "anyvalue" . getBytes ( ) , new TimestampClock ( 1L ) ) ; rm . apply ( ) ; ColumnFamilyStore store = Table . open ( oldCfm . tableName ) . getColumnFamilyStore ( oldCfm . cfName ) ; assert store != null ; store . forceBlockingFlush ( ) ; int fileCount = DefsTable . getFiles ( oldCfm . tableName , oldCfm . cfName ) . size ( ) ; assert fileCount > 0 ; final String cfName = "St4ndard1Replacement" ; new RenameColumnFamily ( oldCfm . tableName , oldCfm . cfName , cfName ) . apply ( ) ; assert ! ( DatabaseDescriptor . getTableDefinition ( ks . name ) . cfMetaData ( ) . containsKey ( oldCfm . cfName ) ) ; assert DatabaseDescriptor . getTableDefinition ( ks . name ) . cfMetaData ( ) . containsKey ( cfName ) ; assert ( DefsTable . getFiles ( oldCfm . tableName , cfName ) . size ( ) ) == fileCount ; store = Table . open ( oldCfm . tableName ) . getColumnFamilyStore ( cfName ) ; assert store != null ; <START_BUG> ColumnFamily cfam = store . getColumnFamily ( QueryFilter . getSliceFilter ( dk , new QueryPath ( cfName ) , "" . getBytes ( ) , "" . getBytes ( ) , null , false , 1000 ) ) ; <END_BUG> assert ( cfam . getSortedColumns ( ) . size ( ) ) == 100 ; rm = new RowMutation ( ks . name , dk . key ) ; rm . add ( new QueryPath ( cfName , null , "col5" . getBytes ( ) ) , "updated" . getBytes ( ) , new TimestampClock ( 2L ) ) ; rm . apply ( ) ; store . forceBlockingFlush ( ) ; cfam = store . getColumnFamily ( QueryFilter . getNamesFilter ( dk , new QueryPath ( cfName ) , "col5" . getBytes ( ) ) ) ; assert ( cfam . getColumnCount ( ) ) == 1 ; assert Arrays . equals ( cfam . getColumn ( "col5" . getBytes ( ) ) . value ( ) , "updated" . getBytes ( ) ) ; } @ Test public void addNewKS ( ) throws IOException , InterruptedException , ExecutionException , ConfigurationException { } @ Test public void dropKS ( ) throws IOException , InterruptedException , ExecutionException , ConfigurationException { } @ Test public void renameKs ( ) throws IOException , InterruptedException , ExecutionException , ConfigurationException { } @ Test public void createEmptyKsAddNewCf ( ) throws IOException , InterruptedException , ExecutionException , ConfigurationException { } }

Fix:
ColumnFamily cfam = store . getColumnFamily ( QueryFilter . getSliceFilter ( dk , new QueryPath ( cfName ) , "" . getBytes ( ) , "" . getBytes ( ) , false , 1000 ) ) ;